Made rqworker and rqinfo respect db parameters from --url

When starting the rqworker and rqinfo scripts with an `--url` parameter containing a non default database, e.g. `redis://localhost:6379/2`, both scripts connected to db 0 instead of the desired database. Fixed this behavior by ignoring the `--host`, `--port` and `--db` arguments if `--url` is present.

Also fixed another issue with the rqinfo script, in which it defaulted to only the 'default' queue instead of finding all available queues using `Queue.all()`.